2. Field of the Invention
This invention relates to a magnetic reproducing device, and more particularly to a magnetic reproducing device which includes a system for obtaining an address signal to identify specific fields and/or frames of a video signal recorded on a tape.
2. Description of the Prior Art
In order to edit video signals rapidly and precisely, it has been proposed in the prior art to record address signals on magnetic tape in addition to the video signal. The address signals can be written in various codes, but the SMPTE time code signal is recommended as an American National Standard, and the EBU time code signal is recommended as a standard code for 625 line/50 field television tape recordings. In the art, such code signals are recorded on a record medium along its longitudinal track and they can be read from the record medium over a fairly broad range of tape speeds. In the case where the record medium is stopped or transported at very low speeds, however, the reproduction of the time code signals becomes impossible. Upon editing a video tape by a video tape recorder, it is very advantageous for an editor to be able to choose individual frames presented visually at very low tape speeds, but the disadvantage of this method of operation is that the address of a chosen frame cannot be readily known with prior art systems. Further, when there are portions of the record media on which a time code signal is not recorded, or which contain drop-out, or when the time code signal cannot be reproduced because of head-clogging, the address of a chosen frame cannot be known.
In a video tape recorder having still and slow-motion reproduction modes, in order to obtain an address signal in such reproduction modes, it has been proposed to insert in the vertical blanking period of the recorded television signal a time code signal corresponding to an address. Such a time code signal is most suitable for a VTR, such as that, proposed in the U.S. Patent Application Ser. No. 677,815, in which a reproduced signal without guard band noise can be obtained regardless of the tape speed and tape running direction. However, since the vertical blanking signal is positioned on the end portion of the recorded track, there is a possibility that it will not be properly reproduced in the slow or still mode. When a magnetic head is positioned near an end portions of a recorded track, the contact condition between the magnetic head and the magnetic tape is deteriorated, and accordingly, there is an increased possibility that the vertical blanking signal cannot be reproduced.